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/**
* Copyright (C) 2018-present MongoDB, Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the Server Side Public License, version 1,
* as published by MongoDB, Inc.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* Server Side Public License for more details.
*
* You should have received a copy of the Server Side Public License
* along with this program. If not, see
* <http://www.mongodb.com/licensing/server-side-public-license>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the Server Side Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#include "mongo/db/update_index_data.h"
#include "mongo/bson/util/builder.h"
namespace mongo {
namespace {
enum class NumericPathComponentResult {
kNumericOrDollar,
kConsecutiveNumbers,
kNonNumericOrDollar
};
NumericPathComponentResult checkNumericOrDollarPathComponent(const FieldRef& path,
size_t pathIdx,
const StringData& pathComponent) {
if (pathComponent == "$"_sd) {
return NumericPathComponentResult::kNumericOrDollar;
}
if (FieldRef::isNumericPathComponentLenient(pathComponent)) {
// Peek ahead to see if the next component is also all digits. This implies that the
// update is attempting to create a numeric field name which would violate the
// "ambiguous field name in array" constraint for multi-key indexes. Break early in this
// case and conservatively return that this path affects the prefix of the consecutive
// numerical path components. For instance, an input such as 'a.0.1.b.c' would return
// the canonical index path of 'a'.
if ((pathIdx + 1) < path.numParts() &&
FieldRef::isNumericPathComponentLenient(path.getPart(pathIdx + 1))) {
return NumericPathComponentResult::kConsecutiveNumbers;
}
return NumericPathComponentResult::kNumericOrDollar;
}
return NumericPathComponentResult::kNonNumericOrDollar;
}
/**
* Checks whether a given Document path overlaps with an indexed path
*/
bool pathOverlaps(const FieldRef& path, const FieldRef& indexedPath) {
size_t pathIdx = 0;
size_t indexedPathIdx = 0;
while (pathIdx < path.numParts() && indexedPathIdx < indexedPath.numParts()) {
auto pathComponent = path.getPart(pathIdx);
// The first part of the path must always be a valid field name, since it's not possible to
// store a top-level array or '$' field name in a document.
if (pathIdx > 0) {
NumericPathComponentResult res =
checkNumericOrDollarPathComponent(path, pathIdx, pathComponent);
if (res == NumericPathComponentResult::kNumericOrDollar) {
++pathIdx;
continue;
}
if (res == NumericPathComponentResult::kConsecutiveNumbers) {
// This case implies that the update is attempting to create a numeric field name
// which would violate the "ambiguous field name in array" constraint for multi-key
// indexes. Break early in this case and conservatively return that this path
// affects the prefix of the consecutive numerical path components. For instance, an
// input path such as 'a.0.1.b.c' would match indexed path of 'a.d'.
return true;
}
}
StringData indexedPathComponent = indexedPath.getPart(indexedPathIdx);
if (pathComponent != indexedPathComponent) {
return false;
}
++pathIdx;
++indexedPathIdx;
}
return true;
}
} // namespace
UpdateIndexData::UpdateIndexData() : _allPathsIndexed(false) {}
void UpdateIndexData::addPath(const FieldRef& path) {
_canonicalPaths.insert(getCanonicalIndexField(path));
}
void UpdateIndexData::addPathComponent(StringData pathComponent) {
_pathComponents.insert(pathComponent.toString());
}
void UpdateIndexData::allPathsIndexed() {
_allPathsIndexed = true;
}
void UpdateIndexData::clear() {
_canonicalPaths.clear();
_pathComponents.clear();
_allPathsIndexed = false;
}
bool UpdateIndexData::isEmpty() const {
return !_allPathsIndexed && _canonicalPaths.empty() && _pathComponents.empty();
}
bool UpdateIndexData::mightBeIndexed(const FieldRef& path) const {
if (_allPathsIndexed) {
return true;
}
for (const auto& indexedPath : _canonicalPaths) {
if (pathOverlaps(path, indexedPath)) {
return true;
}
}
for (const auto& pathComponent : _pathComponents) {
for (size_t partIdx = 0; partIdx < path.numParts(); ++partIdx) {
if (pathComponent == path.getPart(partIdx)) {
return true;
}
}
}
return false;
}
bool UpdateIndexData::_startsWith(const FieldRef& a, const FieldRef& b) const {
return (a == b) || (b.isPrefixOf(a));
}
FieldRef UpdateIndexData::getCanonicalIndexField(const FieldRef& path) {
if (path.numParts() <= 1)
return path;
// The first part of the path must always be a valid field name, since it's not possible to
// store a top-level array or '$' field name in a document.
FieldRef buf(path.getPart(0));
for (size_t i = 1; i < path.numParts(); ++i) {
auto pathComponent = path.getPart(i);
NumericPathComponentResult res = checkNumericOrDollarPathComponent(path, i, pathComponent);
if (res == NumericPathComponentResult::kNumericOrDollar) {
continue;
}
if (res == NumericPathComponentResult::kConsecutiveNumbers) {
break;
}
buf.appendPart(pathComponent);
}
return buf;
}
bool UpdateIndexData::isComponentPartOfCanonicalizedIndexPath(StringData pathComponent) {
return pathComponent != "$"_sd && !FieldRef::isNumericPathComponentLenient(pathComponent);
}
} // namespace mongo
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